complex mesh slicing and cutting

[system]

I’ve been using the slicing and trim brushes alot recently on models of skulls based off of ct scans. I’m running into a few issues that I’m wondering if someone might have a solution to. Most of the time slicing will work great, but every once in a while when it gets to the fill holes algorithm it will fill in entire spaces that should be empty with very thin planes. This image demonstrates this, on the left is the original model, and on the right a bit has been sliced off of the top - as you can see a plane fills the entire top rather than just the edges where the geometry would be ideally. What I’ve had to resort to is removing that fill holes polygroup then export the rest out to maya to fill the holes manually, this can take a long time though so an automated method would be much better.
Just a shot in the dark if anyone has an easier way of dealing with this?

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[beta_channel]

On a complex shape like that you’re bound to get errors where you’re looking for a rim rather than a flat surface. Rather than exporting out to maya you could delete the new sliced polygroup and dynamesh the object, which should fill in the rim correctly as it is going to look for the closest points to generate the new mesh. I would duplicate the mesh before doing this so you can increase your subD levels and project your detail back from the original mesh.

[zber2]

Sadly, Dynamesh won’t work in this as it always wants to close the hole as well as the rim section. I have found that the new ‘CurveBridge’ brush will work well in this instance. See page 45 in the ZBrush4_R6_whats_new.pdf in your Documentation folder. As an example, you could use the ‘SliceCurve’ brush to do the slice, then hide and delete the polygroups you don’t want, then use the ‘CurveBridge’ brush to bridge the gap. I haven’t tried this on a high density mesh though so I don’t know what the outcome would be in that case.

[system]

Ah awesome, I was playing with this earlier just didn’t think to use it for this. The curve bridge brush works awesome for this! That took my about over an hour to do by hand before ugh

Sadly, Dynamesh won’t work in this as it always wants to close the hole as well as the rim section. I have found that the new ‘CurveBridge’ brush will work well in this instance. See page 45 in the ZBrush4_R6_whats_new.pdf in your Documentation folder. As an example, you could use the ‘SliceCurve’ brush to do the slice, then hide and delete the polygroups you don’t want, then use the ‘CurveBridge’ brush to bridge the gap. I haven’t tried this on a high density mesh though so I don’t know what the outcome would be in that case.

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[zber2]

Great! I’m glad it worked out for you.